WO2006006630A1 - Magnetoresistive device, method for manufacturing magnetoresistive device and magnetic random access memory - Google Patents

Abstract

A method for manufacturing a magnetoresistive device comprises a step for forming an antiferromagnetic layer on the upper surface of a substrate, a step for forming a first fixed ferromagnetic layer on the antiferromagnetic layer on the upper surface of the substrate, a step for exposing the first fixed ferromagnetic layer to a gas containing oxygen atoms at a pressure of not less than 5 × 10-7 Pa and not more than 1 × 10-4 Pa, a step for forming a second fixed ferromagnetic layer on the first fixed ferromagnetic layer, a step for forming a tunnel barrier layer on the second fixed ferromagnetic layer, and a step for forming a free ferromagnetic layer on the tunnel barrier layer. In this connection, an oxygen gas having a pressure (partial pressure) of not less than 5 × 10-7 Pa and not more than 1 × 10-4 Pa exemplifies the gas containing oxygen atoms. In this method for manufacturing a magnetoresistive device, the second fixed ferromagnetic layer is so formed as to have a thickness of more than 0 and not more than 1 nm.

Description

 Specification

 Magnetoresistive element, method for manufacturing magnetoresistive element, and magnetic random access memory

 Technical field

 The present invention relates to a magnetoresistive effect element, a magnetoresistive effect element manufacturing method, and a magnetic random access memory, and more particularly to a magnetoresistive effect element using a magnetic tunnel junction and a magnetoresistive effect element manufacturing method, and a magnetic random access memory. About.

 Background art

 [0002] A magnetic tunnel junction (MTJ) composed of two ferromagnetic layers (a pinned ferromagnetic layer and a free ferromagnetic layer) and a tunnel barrier layer (tunnel insulating layer) sandwiched between these ferromagnetic layers : Magnetic Tunneling Junction). The resistance of a magnetic tunnel junction varies greatly depending on the relative direction of magnetization of the ferromagnetic layer. Such a phenomenon is called a tunneling magneto-resistance effect (TMR effect). By detecting the resistance of the magnetic tunnel junction, it is possible to determine the magnetization direction of the ferromagnetic layer. Such a property of the magnetic tunnel junction is applied to a magnetic random access memory (MRAM) that holds data in a nonvolatile manner as a magnetoresistive device including the magnetic tunnel junction.

 [0003] The MRAM is configured by arranging memory cells each including an MTJ in a matrix. Magnetization of the pinned ferromagnetic layer as one of the two ferromagnetic layers included in MTJ is fixed, and the magnetization of the free ferromagnetic layer as the other ferromagnetic layer can be reversed. Provided. Data is stored as the direction of the magnetic field of the free ferromagnetic layer. Data is written by passing a current in the vicinity of the magnetic tunnel junction and inverting the magnetic field of the free ferromagnetic layer by the magnetic field generated by the current. Data is read out by detecting the direction of the magnetic layer of the free ferromagnetic layer using the TMR effect.

[0004] Various magnetic interactions act between the fixed ferromagnetic layer and the free ferromagnetic layer. The main ones are nail coupling magnetic field and leakage magnetic field. With such magnetic interaction, the magnitude of the magnetic field when the free ferromagnetic layer switches parallel force antiparallel And the magnitude of the magnetic field when switching in the parallel direction is different. The difference between the magnitudes of these reversal fields is called the offset magnetic field. When such an offset magnetic field exists, the disturbance between memory cells becomes large. In that case, it becomes easy to cause a magnetization reversal failure, and thus the manufacturing yield decreases. Therefore, the magnitude of the offset magnetic field needs to be zero.

 [0005] As a method of making the offset magnetic field zero, for example, as described in USP6292389, a method of setting the upper and lower surfaces of the fixed ferromagnetic layer to cancel each other, as described in USP6233172, a nail cup There is a method of canceling each other by making the ring magnetic field and the leakage magnetic field the same magnitude. By using such a method, the offset magnetic field can be adjusted to zero.

 [0006] However, the above-mentioned USP6292389, USP6233172 [the magnetoresistive effect element described herein] [In this case, if the surface roughness of the film under the tunnel barrier layer is rough, the tunnel noor is formed thereon. Since the thickness of the layer is as thin as 1 nm, it is difficult to form a tunnel barrier layer continuously. In such a case, a leak spot may be formed in the tunnel barrier layer, and the quality of the tunnel barrier layer may be deteriorated. Therefore, it is necessary to make the lower surface of the tunnel barrier layer as smooth as possible.

 [0007] With a magnetoresistive element such as USP6292389 and USP6233172, the nail coupling magnetic field cannot be made completely zero. That is, the offset magnetic field can be zeroed by this method. The nail coupling magnetic field has a finite value. In the above document, the cancellation is performed by the leakage magnetic field of the fixed ferromagnetic layer force or the nail coupling magnetic field of the surface force under the fixed ferromagnetic layer. In such a case, it becomes difficult to suppress variations in characteristics because the number of parameters to be controlled increases other than the nail coupling magnetic field.

 [0008] As a method of smoothing the lower surface of the tunnel barrier layer, J. Appl. Phys., Vol. 93, No.

10, Part 2 & 3, 2003, p. 8373 [As shown, it has been reported that a magnetoresistive element including a magnetic junction is formed by low-pressure DC magnetron sputtering. It has been reported that this can reduce the size of the nail coupling to 2-30e. However, in the magnetoresistive effect element shown in the above document, the fixed ferromagnetic layer It is conceivable that the exchange coupling magnetic field between the pinned ferromagnetic layer and the antiferromagnetic layer is lowered when is smoothed. In general, an antiferromagnetic film grows on a base film. As this crystal growth proceeds, the exchange coupling magnetic field increases. On the other hand, as the crystal growth proceeds, the surface roughness due to the crystal grains increases. In other words, the exchange coupling magnetic field and the smoothness of the fixed ferromagnetic layer have a trade-off relationship.

 [0009] A technique capable of improving the quality of the tunnel barrier layer is desired. A technology that can make the nail coupling magnetic field zero is desired. A technique capable of improving the characteristics of the magnetoresistive element is desired. A technology that can improve the manufacturing yield is desired.

 [0010] In connection with the above description, JP-A-2002-158381 discloses a ferromagnetic tunnel junction device and a method for manufacturing the same. In this ferromagnetic tunnel junction device, an insulating layer or an amorphous magnetic layer is sandwiched between an antiferromagnetic layer containing Mn and the first and twenty-second ferromagnetic layers formed on the antiferromagnetic layer. A magnetic pinned layer having an elliptical structure, a tunnel barrier layer formed on the magnetic pinned layer, and a magnetic free layer formed on the tunnel barrier layer. The insulating layer or amorphous magnetic layer of the magnetic pinned layer may have a function of preventing diffusion of Mn contained in the antiferromagnetic layer. The first ferromagnetic layer of the magnetization pinned layer may be exposed to an oxidizing atmosphere, a nitriding atmosphere, or a carbonizing atmosphere to form an insulating layer of the magnetic pinned film.

 [0011] Also, Japanese Patent Application Laid-Open No. 11-54814 discloses a method for manufacturing a ferromagnetic tunnel junction device. This method for manufacturing a ferromagnetic tunnel junction device is a method for manufacturing a ferromagnetic tunnel junction device having a structure in which a tunnel barrier layer is sandwiched between a first ferromagnetic layer and a second ferromagnetic layer. The method includes forming a tunnel barrier layer by forming a conductive layer having a metal or semiconductor power and then introducing oxygen into a vacuum and oxidizing the surface of the conductive layer with a natural acid. After forming the first ferromagnetic layer, it may include a step of introducing oxygen into vacuum to oxidize the surface of the first ferromagnetic layer.

[0012] Japanese Patent Application Laid-Open No. 2000-196165 discloses a magnetic tunnel element and a method for manufacturing the same. This magnetic tunnel junction device manufacturing method includes a metal, an alloy, an intermetallic compound, an oxide, or a nitrogen containing at least one selected from the group consisting of Fe, Ni, and Co. Forming a lower magnetic layer made of an oxide, oxidizing the lower magnetic layer, forming a barrier film on the lower magnetic layer, and forming Fe, Ni and Co on the noria film. Forming an upper magnetic layer made of a metal, an alloy, an intermetallic compound, an oxide or a nitride containing at least one selected from the group consisting of:

 [0013] In addition, Japanese Patent Application Laid-Open No. 2004-119903 discloses a magnetoresistive effect element and a method for manufacturing the same. This magnetoresistive element manufacturing method includes (A) a step of forming an antiferromagnetic layer on the upper surface side of a substrate in a vacuum container, and (B) after forming the antiferromagnetic layer, in the vacuum container. Introducing an oxidizing gas (e.g., oxygen gas), (C) exhausting the acidic gas from the vacuum vessel, and (D) exhausting the acidic gas, Forming a fixed ferromagnetic layer on the ferromagnetic layer; (E) forming a tunnel barrier layer on the first ferromagnetic layer; and (F) on the tunnel barrier layer. Forming a second ferromagnetic layer. Further, the magnetoresistive element manufacturing method includes (G) a step of forming an antiferromagnetic layer on the upper surface side of the substrate and (H) an antiferromagnetic layer in an atmosphere containing an oxidizing gas (eg, oxygen gas). Forming a fixed ferromagnetic layer on the layer; (I) forming a tunnel barrier layer on the fixed ferromagnetic layer; and ω forming a free ferromagnetic layer on the tunnel barrier layer. Including the step of. The partial pressure of the acidic gas during the step (ii) is determined so that the formed first ferromagnetic layer has conductivity.

 [0014] Further, Japanese Patent Application Laid-Open No. 2000-150984 discloses a technique of a magnetic tunnel element using an ozone oxidation insulating film. The magnetic tunnel element using the ozonate insulating film is a magnetic tunnel element having a hard magnetic film and a soft magnetic film having mutually different coercive forces, and an insulating film interposed between the two. The film is oxidized in a mixture of oxygen and ozone.

[0015] In addition, Japanese Unexamined Patent Application Publication No. 2003-258335 discloses a method for manufacturing a tunnel magnetoresistive effect element. This is because the first ferromagnetic layer, the tunnel insulating layer, and the second ferromagnetic layer are laminated in this order on the substrate, and the relative angle difference between the first ferromagnetic layer and the second ferromagnetic layer in the magnetic field direction is different. This is a method of manufacturing a tunnel magnetoresistive element having different tunnel magnetoresistance. A first step of forming a conductive layer as the tunnel insulating layer precursor; and a second step of oxidizing the conductive layer in an oxygen atmosphere. In the first step, the conductive layer is 0.4 on Dustrom At least one kind of Al, Mg, Si, Ta is formed at a deposition rate of Z seconds or less. The tunnel insulating layer may be formed by performing the first step and the second step a plurality of times. An oxidation method that can be oxidized in vacuum in the second step may be a natural oxidation method, a plasma oxidation method, or a radical oxidation method.

 Disclosure of the invention

 Accordingly, an object of the present invention is to provide a magnetoresistive element capable of improving the quality of a tunnel barrier layer in a magnetic tunnel junction, a method for manufacturing the magnetoresistive element, and a magnetic random access memory. It is in.

[0017] Another object of the present invention is to provide a magnetoresistive effect element, a magnetoresistive effect element manufacturing method, and a magnetoresistive random access memory capable of making a nail coupling magnetic field in a magnetic tunnel junction zero. There is.

Still another object of the present invention is to provide a magnetoresistive effect element capable of improving the characteristics of the magnetic tunnel junction, a method for manufacturing the magnetoresistive effect element, and a magnetic random access memory.

 Another object of the present invention is to provide a magnetoresistive effect element capable of improving the manufacturing yield, a magnetoresistive effect element manufacturing method, and a magnetic random access memory.

In the aspect of the present invention, the method of manufacturing a magnetoresistive element includes forming an antiferromagnetic layer on the upper surface side of the substrate, and forming a first fixed ferromagnetic layer on the antiferromagnetic layer on the upper surface side of the substrate. Forming a layer, exposing the first pinned ferromagnetic layer to a gas containing oxygen atoms at a pressure of 5 X 10 ^_7 Pa or more and 1 X 10 ^_4 Pa or less, and Forming a second pinned ferromagnetic layer on the first layer, forming a tunnel barrier layer on the second pinned ferromagnetic layer, and forming a free ferromagnetic layer on the tunnel barrier layer. The However, the gas containing oxygen atoms is exemplified by oxygen gas having a pressure (or partial pressure) of 5 ^× 10 ^_7 Pa or more and 1 ^× 10 ^_4 Pa or less. In the above magnetoresistive element manufacturing method, the second pinned ferromagnetic layer is formed so that the film thickness is greater than 0 and less than or equal to 1 nm.

[0021] In another aspect of the present invention, a method for manufacturing a magnetoresistive effect element includes: forming an antiferromagnetic layer on an upper surface side of a substrate; and a first fixed ferromagnetic layer on the antiferromagnetic layer. Forming And exposing the first pinned ferromagnetic layer to a gas containing oxygen atoms at a pressure of 5 X 10 ^_7 Pa or more and less than 1 X 10 ^_4 Pa, and a tunnel barrier layer on the first pinned ferromagnetic layer. And forming a free ferromagnetic layer on the tunnel barrier layer. However, a gas containing oxygen atoms is exemplified by an oxygen gas having a pressure (or partial pressure) of 5 ^× 10 ^_7 Pa or more and less than 1 ^× 10 ^_4 Pa.

[0022] In the method of manufacturing a magnetoresistive effect element, the step of exposing the first pinned ferromagnetic layer to a gas containing oxygen atoms is performed at a pressure of 1 X 10 ^_6 Pa or more and 1 X 10 ^_5 Pa or less. It is more desirable to expose to gases containing oxygen atoms. The gas containing oxygen atoms is preferably a gas containing at least one of oxygen gas, water, methanol, and ethanol gas. The first pinned ferromagnetic layer force includes a film containing one of CoFe, NiFe, CoFeB, and CoFeCr. In the method of manufacturing a magnetoresistive effect element described above, the surface roughness of the first pinned ferromagnetic layer on the tunnel barrier layer side is smaller than the surface roughness of the lower layer than the first pinned ferromagnetic layer.

 In another aspect of the present invention, the magnetoresistive effect element includes an antiferromagnetic layer, a first pinned ferromagnetic layer, a second pinned ferromagnetic layer, a tunnel barrier layer, and a free ferromagnetic layer. It comprises. The antiferromagnetic layer is formed on the upper surface side of the substrate. The first pinned ferromagnetic layer is formed on the antiferromagnetic layer. The second pinned ferromagnetic layer is formed on the first pinned ferromagnetic layer. The tunnel barrier layer is formed on the second pinned ferromagnetic layer. The free ferromagnetic layer is formed on the tunnel barrier layer. The region of the surface of the first pinned ferromagnetic layer on the second pinned ferromagnetic layer side has a higher oxygen concentration than the other regions. The surface roughness of the first pinned ferromagnetic layer on the tunnel barrier layer side is smaller than the surface roughness of the layer below the first pinned ferromagnetic layer. Here, the first pinned ferromagnetic layer includes a pinned ferromagnetic layer A, a nonmagnetic layer, and a pinned ferromagnetic layer B, and is pinned with the pinned ferromagnetic layer A by antiferromagnetic layer coupling via the nonmagnetic layer. The direction of the magnetic field of the ferromagnetic layer B6 is antiparallel. In the above magnetoresistive element, the thickness of the second pinned ferromagnetic layer is greater than 0 and less than or equal to 1 nm.

In another aspect of the present invention, the magnetoresistive effect element includes an antiferromagnetic layer, a first pinned ferromagnetic layer, a tunnel barrier layer, and a free ferromagnetic layer. The antiferromagnetic layer is formed on the upper surface side of the substrate. The first pinned ferromagnetic layer is formed on the antiferromagnetic layer. . The tunnel barrier layer is formed on the first pinned ferromagnetic layer. The free ferromagnetic layer is formed on the tunnel barrier layer. The surface roughness of the first pinned ferromagnetic layer on the tunnel barrier layer side is smaller than the surface roughness of the layer below the first pinned ferromagnetic layer. The magnetoresistive element includes a film containing one of the first fixed ferromagnetic layer forces CoFe, NiFe, CoFeB, and CoFeCr.

 In another aspect of the present invention, a magnetic random access memory includes a plurality of word lines, a plurality of bit lines, and a plurality of magnetoresistive elements. The plurality of word lines extend in the first direction (X direction). The plurality of bit lines extend in a second direction (Y direction) substantially perpendicular to the first direction (X direction). The plurality of magnetoresistive elements are provided at each of the intersections of the plurality of word lines and the plurality of bit lines, and are described in any one of the above items.

 Brief Description of Drawings

 FIG. 1 is a cross-sectional view showing a configuration of a first embodiment of a magnetoresistive element of the present invention.

FIG. 2 is a cross-sectional view showing a first embodiment of a method for producing a magnetoresistive element of the present invention.

 FIG. 3 is a cross-sectional view showing a first embodiment of a method for producing a magnetoresistive element of the present invention.

 FIG. 4 is a cross-sectional view showing a first embodiment of a method for producing a magnetoresistive element of the present invention.

 FIG. 5 is a cross-sectional view showing a first embodiment of a method for producing a magnetoresistive element of the present invention.

 FIG. 6 is a cross-sectional view showing a first embodiment of a method for producing a magnetoresistive element of the present invention.

 [FIG. 7] FIG. 7 is a graph showing the relationship between the processing conditions in the oxygen gas processing and the nail coupling magnetic field.

FIG. 8 is a cross-sectional view showing a configuration of a second embodiment of the magnetoresistance effect element of the present invention. FIG. 9 is a cross-sectional view showing a second embodiment of the method for producing a magnetoresistive element of the present invention.

 FIG. 10 is a cross-sectional view showing a second embodiment of the method for manufacturing a magnetoresistive element of the present invention.

 FIG. 11 is a cross-sectional view showing a second embodiment of the method for producing a magnetoresistive element of the present invention.

 FIG. 12 is a cross-sectional view showing a second embodiment of the method for producing a magnetoresistive element of the present invention.

 FIG. 13 is a cross-sectional view showing a second embodiment of the method for manufacturing a magnetoresistive element of the present invention.

 FIG. 14 is a cross-sectional view showing a second embodiment of the method for producing a magnetoresistive element of the present invention.

 FIG. 15 is a graph showing the relationship between the processing conditions in the oxygen gas processing and the nail coupling magnetic field.

 FIG. 16 is a graph showing the rate of change in magnetic field resistance of a magnetoresistive effect element manufactured by using the magnetoresistive effect element manufacturing method.

 FIG. 17 is a graph showing the bias voltage dependence of the MR ratio between a magnetoresistive effect element manufactured using a magnetoresistive effect element manufacturing method and a magnetoresistive effect element manufactured using a conventional method. .

 FIG. 18 is a cross-sectional view showing a configuration of a memory cell in which the magnetoresistive element of the present invention is applied to a magnetic random access memory.

 FIG. 19 is a block diagram showing a configuration of an MRAM using memory cells.

 BEST MODE FOR CARRYING OUT THE INVENTION

[0027] This application is related to US patent application numbers 10Z520, 652 and 10Z702,655. The disclosure content of these applications is incorporated herein by reference.

Hereinafter, a magnetoresistive effect element, a magnetoresistive effect element manufacturing method, and a magnetic random access memory according to the present invention will be described with reference to the accompanying drawings.

[0029] [First embodiment] A magnetoresistive effect element and a method of manufacturing the magnetoresistive effect element according to the first embodiment of the present invention will be described with reference to the accompanying drawings.

 First, the configuration of the magnetoresistance effect element according to the first example of the present invention will be described. Here, a magnetoresistive element applied to a magnetic random access memory (MRAM) will be described. FIG. 1 is a cross-sectional view showing the configuration of the first embodiment of the magnetoresistive element of the present invention. The magnetoresistive effect element 30 is provided on the upper surface side of the substrate 20, and includes a seed layer 2, an antiferromagnetic layer 3, a fixed ferromagnetic layer A4, a nonmagnetic film 5, a fixed ferromagnetic layer B6, a tunnel barrier layer 7, A free ferromagnetic layer 8 and a cap layer 9 are provided. The seed layer 2 is connected to the lower electrode 1 on the substrate 20 side, and the cap layer 9 is connected to the upper electrode (not shown) on the opposite side.

 [0031] The substrate 20 is a substrate in which an element exemplified by CMOS (for MRAM) is formed on a semiconductor substrate. The lower electrode 1 is provided on the upper surface side of the substrate 20. As the lower electrode 1, for example, a conductive material such as Ta, TaN, Rh, Ir is used. The same applies to the upper electrode (not shown). The seed layer 2 is provided on the lower electrode 1. For the seed layer 2, for example, a material such as NiFe, CoFe, NiCr, or NiFeCr is used. The antiferromagnetic layer 3 is provided on the seed layer 2. As the antiferromagnetic layer 3, for example, an antiferromagnetic material such as IrMn, FeMn, PtMn, Ni02, or a-Fe203 is used. The fixed ferromagnetic layer A4 is provided on the antiferromagnetic layer 3. As the fixed ferromagnetic layer A4, for example, a ferromagnetic material such as CoFe, NiFe, CoFeB, or CoFeCr is used. The nonmagnetic layer 5 is provided on the pinned ferromagnetic layer A4. As the nonmagnetic layer 5, for example, a nonmagnetic material such as Ru or Cu is used. The fixed ferromagnetic layer B6 is provided on the nonmagnetic layer 5. As the fixed ferromagnetic layer B6, for example, a ferromagnetic material such as CoFe, NiFe, CoFeB, and CoFeCr is used. Before the tunnel barrier layer 7 is formed, an oxygen group is adsorbed on the surface of the fixed ferromagnetic layer B6 by introducing a gas containing oxygen atoms into a vacuum at a predetermined pressure and exposing the surface thereof. As the gas containing oxygen atoms, oxygen gas, methanol, water, ethanol and the like are used.

[0032] The tunnel barrier layer 7 is provided on the fixed ferromagnetic layer B6. The tunnel barrier layer 7 is an insulating nonmagnetic material formed by, for example, oxidizing A1 using oxygen radicals, oxygen plasma, ozone, or the like. The free ferromagnetic layer 8 is composed of the tunnel barrier layer 7 It is provided above. As the free ferromagnetic layer 8, a single layer film or a laminated film of a ferromagnetic material such as NiFe, CoFeB, CoFe, and CoFeCr is used. The cap layer 9 is provided on the free ferromagnetic layer 8. For the cap layer 9, for example, a conductive material such as Ta, TaN, Rh, Ir is used.

In FIG. 1, the unevenness of each film shows general unevenness that is not intentional and can be naturally formed during film formation. However, the tunnel barrier layer 7 is a smooth layer with reduced irregularities on the surface of the free ferromagnetic layer 8 side. Along with this, the layers above it have also become smooth.

 Next, a method for manufacturing a magnetoresistive effect element according to the first embodiment of the present invention will be described. 2 to 6 are sectional views showing a method of manufacturing a magnetoresistive effect element according to the first embodiment of the present invention.

 Referring to FIG. 2, lower electrode 1, seed layer 2, antiferromagnetic layer 3, pinned ferromagnetic layer A4, nonmagnetic layer 5, and pinned ferromagnetic layer B6 are formed in this order on the upper surface of substrate 1. Is done. Film formation is performed using a notched method, an ion beam sputtering method, or the like.

 Next, referring to FIG. 3, by introducing oxygen gas (or a gas containing oxygen gas at the same partial pressure) into the vacuum, the surface of the fixed ferromagnetic layer B6 is exposed to oxygen gas. Adsorb oxygen on the surface. At this time, as will be described later with reference to FIG. 7, the pressure (partial pressure) of the oxygen gas is made very small. Thereby, the surface of the pinned ferromagnetic layer B6 has only oxygen adsorbed or has an extremely thin layer containing a large amount of oxygen, and there is no oxide layer of the pinned ferromagnetic layer B6. It may be a substance containing an OH group such as methanol, water, and ethanol, or a gas combining two or more of oxygen gas, methanol, water, and ethanol. By the above method, when the film 7a for the tunnel barrier layer is formed, the wettability of the tunnel barrier layer film 7a to the fixed ferromagnetic layer B6 is improved. It becomes possible to do.

Referring to FIG. 4, tunnel barrier film 7a is formed on fixed ferromagnetic layer B6 after the surface treatment. Film formation is performed using a sputtering method, an ion beam sputtering method, or the like. As described above, the tunnel barrier film 7a is a continuous film without pinholes even if it is thin. At this time, the surface roughness of the film (average surface roughness Ra, maximum surface roughness Rmax) decreases, and the unevenness is reduced. There will be no film. At the same time, the period of the surface roughness does not follow the undulation of the surface of the lower layer such as the fixed ferromagnetic layer B6, and the undulation period becomes shorter.

 Referring to FIG. 5, tunnel barrier layer film 7a is oxidized using oxygen plasma. Instead of oxygen plasma, oxygen radicals or ozone may be used for oxidation. As a result, the tunnel barrier layer film 7 a is oxidized and becomes an insulating tunnel barrier layer 7. The tunnel barrier layer 7 is a thin, continuous layer without pinholes.

 Referring to FIG. 6, a free ferromagnetic layer 8 and a cap layer 9 are formed in this order on the tunnel barrier layer 7. Thereafter, an upper electrode (not shown) is formed.

 As described above, the manufacturing method of the magnetoresistive effect element is performed. In addition, the method of FIG. 2, FIG. 4-6 can also use the other method well-known to those skilled in the art.

FIG. 7 is a graph showing the relationship between the processing conditions in the oxygen gas processing of FIG. 3 and the nail coupling magnetic field. The vertical axis is the magnitude of the nail coupling magnetic field (Oe), and the horizontal axis is the oxygen exposure time (seconds). Each curve in the graph shows a case of different oxygen gas pressure (oxygen gas partial pressure). Oxygen gas pressure, diamonds l X 10 ^_7 Pa, square l X 10 ^_6 Pa, triangle 1 X 10 ^_5 Pa, back is 1 X 10 ^_4 Pa. As shown in Fig. 7, when the oxygen gas pressure is in a very low pressure range between 1 X 10 _ ⁷ Pa and less than 1 X 10 ^_4 Pa, there may be a condition that the Neel coupling magnetic field becomes 0. I understand. That is, the oxygen gas pressure is preferably 1 X 10 " ⁷ Pa or more and less than 1 X 10 ^_4 Pa. However, from the aspect of adjusting the oxygen gas pressure, l X 10 ^_6 Pa or more and l X 10 ^_5 Pa or less The gas pressure is more preferable in production.

In the treatment of oxygen gas in FIG. 3, by changing the pressure of oxygen gas in the oxygen atmosphere to be exposed, the surface of the fixed ferromagnetic layer B6 is in a state where oxygen is adsorbed or an extremely thin layer containing a large amount of oxygen. Can be formed. By changing the surface state of the fixed ferromagnetic layer B6 in this way, the wettability of the tunnel barrier layer film 7a to the fixed ferromagnetic layer B6 is improved, and a continuous film can be formed even if it is thin. That is, the growth method of the tunnel barrier layer film 7a can be changed, and the flatness (surface roughness) of the tunnel barrier layer 7 formed by oxidizing the tunnel barrier layer film 7a can be changed. be able to. As a result, the magnitude of the nail coupling magnetic field can be reduced to zero. In other words, by adjusting the oxygen gas treatment conditions, The size can be set to zero. Similarly, methanol other than oxygen gas, water, ethanol and

Even when a gas that combines two or more of oxygen gas, methanol, water, and ethanol is used, the magnitude of the nail coupling magnetic field can be reduced to zero by adjusting the treatment conditions. In this case, the pressure of the gas is set to be the same as the amount of oxygen atoms contained in the oxygen gas having a pressure of 1 X 10 ^_7 Pa or more and less than 1 X 10 ^_4 Pa, for example. .

 In the present invention, by the oxygen gas treatment of the surface of the pinned ferromagnetic layer B6, the surface force of the tunnel barrier layer 7 on the fixed ferromagnetic layer B6 side and the surface force on the free ferromagnetic layer 8 side are respectively pinned on the tunnel barrier layer 7. It is adjusted to an appropriate surface roughness that does not generate holes. Therefore, according to the present invention, the magnitude of the Neel coupling magnetic field can be reduced to 0 while suppressing the generation of pinholes in the tunnel barrier layer 7.

 [0043] [Second embodiment]

 A magnetoresistive effect element and a magnetoresistive effect element manufacturing method according to a second embodiment of the present invention will be described with reference to the accompanying drawings.

 First, the configuration of the magnetoresistive effect element according to the second example of the present invention will be described. Here, a magnetoresistive element applied to a magnetic random access memory (MRAM) will be described. FIG. 8 is a cross-sectional view showing the configuration of the magnetoresistive effect element according to the second exemplary embodiment of the present invention. The magnetoresistive effect element 30a is provided on the upper surface side of the substrate 20, and includes a seed layer 2, an antiferromagnetic layer 3, a fixed ferromagnetic layer A4, a nonmagnetic film 5, a fixed ferromagnetic layer B6, a boundary layer 10, and a fixed layer. A ferromagnetic layer Cl l, a tunnel barrier layer 7, a free ferromagnetic layer 8, and a cap layer 9. On the substrate 20 side, the seed layer 2 is connected to the lower electrode 1, and on the other side, the cap layer 9 is connected to the upper electrode (not shown). The magnetoresistive effect element 30a of this embodiment is different from that of the first embodiment in that a boundary layer 10 and a fixed ferromagnetic layer CI1 are provided between the fixed ferromagnetic layer B6 and the tunnel barrier layer 7.

[0045] Before forming the pinned ferromagnetic layer C11, the boundary layer 10 is formed by introducing a gas containing oxygen atoms into a vacuum at a predetermined pressure to expose the surface of the pinned ferromagnetic layer B6. . At this time, as will be described later with reference to FIG. 15, the pressure (partial pressure) of the oxygen gas is made very small. As a result, the boundary layer 10 has an oxygen adsorption layer on the surface of the pinned ferromagnetic layer B6, or a large amount of oxygen. It is formed as a very thin (including one to two molecules) layer, and there is no oxide layer of the fixed pinned ferromagnetic layer B6. As the gas containing oxygen atoms, oxygen gas, methanol, water, ethanol and the like are used.

 The fixed ferromagnetic layer C11 is provided on the boundary layer 10. Ferromagnetic materials such as CoFe, NiFe, CoFeB, and CoFeCr are used for the fixed ferromagnetic layer C11. Before forming the tunnel barrier layer 7, an oxygen group may be adsorbed on the surface by introducing a gas containing oxygen atoms into a vacuum at a predetermined pressure to expose the surface of the fixed ferromagnetic layer C11. As gas containing oxygen atoms, oxygen gas, methanol, water, ethanol, etc. are used.

[0047] The other layers are the same as those in the first embodiment, and thus the description thereof is omitted.

[0048] In FIG. 8, the unevenness of each film indicates general unevenness that is not intentional and can be naturally formed during film formation. However, the pinned ferromagnetic layer C11 has a smooth surface with reduced surface irregularities on the free ferromagnetic layer 8 side. Along with this, the layers above it are also smooth.

 Next, a method for manufacturing a magnetoresistive effect element according to the second embodiment of the present invention will be described. 9 to 14 are cross-sectional views showing a method of manufacturing a magnetoresistive effect element according to the second embodiment of the present invention.

 Referring to FIG. 9, lower electrode 1, seed layer 2, antiferromagnetic layer 3, pinned ferromagnetic layer A4, nonmagnetic layer 5, and pinned ferromagnetic layer B6 are formed in this order on the upper surface of substrate 1. Is done. Film formation is performed using a notched method, an ion beam sputtering method, or the like.

Referring to FIG. 10, the surface of fixed ferromagnetic layer B6 is exposed to oxygen gas by introducing oxygen gas (or a gas containing oxygen gas at the same partial pressure) into a vacuum. As a result, the boundary layer 10 is formed on the surface of the pinned ferromagnetic layer B6. The boundary layer 10 is an oxygen adsorption layer on the surface of the fixed ferromagnetic layer B6 or an extremely thin layer containing a large amount of oxygen. A substance containing an OH group such as methanol, water, ethanol, or a gas combining two or more of oxygen gas, methanol, water, and ethanol may be used. By this method, when the pinned ferromagnetic layer C11 is formed, the pinned ferromagnetic layer C11 grows by surface force of the boundary layer 10, so that the boundary layer 10 of the pinned ferromagnetic layer C11 (pinned ferromagnetic layer) B6) Improves. Also, the crystalline state is different from that formed directly on the pinned ferromagnetic layer B6.

 Referring to FIG. 11, the fixed ferromagnetic layer C11 is formed on the boundary layer 10. Film formation is performed using a sputtering method, an ion beam sputtering method, or the like. As described above, since the surface state of the boundary layer 10 is different from that of the normal pinned ferromagnetic layer B6, the surface state force of the formed pinned ferromagnetic layer C11 is different from that of the normal pinned ferromagnetic layer B6. Will be different. At this time, the surface roughness (average surface roughness Ra, maximum surface roughness Rmax) of the film decreases, and the film has less unevenness. At the same time, the period of the surface roughness does not follow the surface waviness of the lower layer (such as the fixed ferromagnetic layer B6), and the waviness period becomes shorter. As a result, when the tunnel barrier layer film 7a is formed, the wettability of the tunnel barrier layer film 7a with respect to the fixed ferromagnetic layer C11 is improved, and the film can be made continuous even without being thin and without pinholes. It becomes possible.

 Referring to FIG. 12, tunnel barrier layer film 7a is formed on fixed ferromagnetic layer C11. Film formation is performed using a sputtering method, an ion beam sputtering method, or the like. As described above, the tunnel barrier layer film 7a is a continuous film that does not have pinholes even if it is thin. Referring to FIG. 13, tunnel barrier film 7a is oxidized using oxygen plasma. Instead of oxygen plasma, oxygen radicals or ozone may be used for oxidation. Accordingly, the tunnel noria film 7a is oxidized to become an insulating tunnel barrier layer 7. The tunnel barrier layer 7 is a thin layer without a continuous pinhole.

 Referring to FIG. 14, a free ferromagnetic layer 8 and a cap layer 9 are formed in this order on the tunnel barrier layer 7. Thereafter, an upper electrode (not shown) is formed.

 As described above, the method for manufacturing a magnetoresistive element is performed. In addition, the method of FIG. 9, FIG. 12-FIG. 14 can also use the other method well-known to those skilled in the art. In this manufacturing method, the same effect can be obtained by forming the remaining pinned ferromagnetic layer C11 in FIG. 11 in a gas atmosphere containing oxygen atoms.

FIG. 15 is a graph showing the relationship between processing conditions and the nail coupling magnetic field in the oxygen gas processing of FIG. The vertical axis is the magnitude of the nail coupling magnetic field (Oe), and the horizontal axis is the film thickness (nm) of the fixed ferromagnetic layer C11. Each curve in the graph shows the case of different oxygen gas pressure (oxygen gas partial pressure). Oxygen gas pressure is l X 10 ^_7 Pa for diamond and 1 X 1 for square 0 ^_b Pa, the triangle is 1 X 10 ^_4 Pa, and the back is 1 X 10 ^_d Pa. The oxygen exposure time is 240 seconds.

[0056] As shown in FIG. 15, when the film thickness of the fixed layer ferromagnetic layer C11 is greater than 0 and less than or equal to 1 ^nm , the oxygen gas pressure is between 1 X 10 ^_7 Pa and less than 1 X 10 ^_3 Pa. It can be seen that there is a condition where the nail coupling magnetic field is zero when in the very low pressure range. ^That is, the oxygen gas pressure is preferably 1 ^× 10 ^_7 Pa or more and 1 ^× 10 ^_4 Pa or less. However, a gas pressure of 1 ^{× 10_6} Pa or more and 1 ^{× 10_5} Pa or less is preferable from the viewpoint of adjustment of oxygen gas pressure. When the film thickness of the fixed layer ferromagnetic layer C11 is greater than lnm, the nail coupling magnetic field is zero.

 [0057] In the treatment of oxygen gas in FIG. 10, the oxygen adsorption layer on the surface of the fixed ferromagnetic layer B6 or the acid layer of the extremely thin fixed ferromagnetic layer B6 is changed by changing the pressure of the oxygen gas in the oxygen atmosphere to be exposed. It is possible to form the boundary layer 10 which is a soot layer. Further, by changing the surface state of the pinned ferromagnetic layer B6 at the boundary layer 10, the crystal state of the pinned ferromagnetic layer C11 can be changed. Since the surface state of the pinned ferromagnetic layer C11 changes, when the tunnel barrier layer film 7a is formed, the tunnel barrier layer film 7a has a surface force on the pinned ferromagnetic layer C11. Film can be formed. That is, the growth method of the tunnel barrier layer film 7a can be changed, and the flatness of the upper surface of the tunnel barrier layer 7 formed by oxidizing the tunnel barrier layer film 7a can be changed. . As a result, the magnitude of the nail coupling magnetic field can be reduced to zero. In other words, the magnitude of the nail coupling magnetic field can be reduced to zero by adjusting the conditions for treating oxygen gas. Similarly, even when using methanol, water, ethanol other than oxygen gas, or a combination of two or more of oxygen gas, methanol, water, and ethanol, nail coupling can be achieved by adjusting the processing conditions. It is possible to reduce the magnitude of the magnetic field to zero.

In the present invention, by the oxygen gas treatment of the surface of the fixed ferromagnetic layer B 6, the surface force of the tunnel barrier layer 7 on the fixed ferromagnetic layer B 6 side and the surface force of the free ferromagnetic layer 8 side are respectively pinned on the tunnel barrier layer 7. It is adjusted to an appropriate surface roughness that does not generate holes. Therefore, according to the present invention, while preventing the generation of pinholes in the tunnel barrier layer 7, The magnitude of the magnetic field can be reduced to zero. At this time, if the material of the pinned ferromagnetic layer B6 is changed, the optimum oxygen exposure conditions differ depending on changes in the wettability of oxygen gas. Good wettability!ヽ Materials have a shorter oxygen exposure time and poor wettability, and materials have a longer oxygen exposure time.

 FIG. 16 is a graph showing the rate of change in magnetic field resistance of the magnetoresistive effect element in the magnetic tunnel junction manufactured by using the above manufacturing method (first example or second example). The vertical axis is the magnetoresistance (MR) change rate (%) of the magnetoresistive effect element (MTJ film), and the horizontal axis is the magnitude (Oe) of the magnetic field applied to the magnetoresistive effect element. Due to the effect of the smoothing of the tunnel barrier layer 7, a resistance change rate of about 40% was obtained at a bias voltage of lOOmV.

 FIG. 17 shows a magnetoresistive effect element (MTJ film) (a) manufactured using the above manufacturing method (first embodiment or second embodiment) (a) and a magnetoresistive effect element (MTJ film) manufactured by a conventional method. It is a graph which shows the bias voltage dependence of MR ratio (resistance change rate (%)) with (b). The magnetoresistive effect element manufactured using the present invention has a higher MR ratio than the conventional magnetoresistive effect element at any bias voltage. This is a result of the improved quality of the tunnel barrier layer 7 (alumina). In other words, the quality of the tunnel barrier layer in the magnetic tunnel junction of the magnetoresistive effect element can be improved, the nail coupling magnetic field can be made zero, and the characteristics of the magnetic tunnel junction of the magnetoresistive effect element can be improved. It becomes.

 [0061] [Third embodiment]

 Embodiments of a magnetic random access memory to which a magnetoresistive effect element and a method of manufacturing a magnetoresistive effect element according to the present invention are applied will be described with reference to the accompanying drawings.

 First, the configuration of an example of a magnetic random access memory to which the magnetoresistive effect element of the present invention is applied will be described. FIG. 18 is a cross-sectional view showing the configuration of a memory cell in which the magnetoresistive element of the present invention is applied to a magnetic random access memory. The memory cell 42 includes the magnetoresistive effect element 30 (or 30a), the lower electrode 1, the upper electrode 31, the MOS transistor 46, the contact wiring 47, and the contact wiring 48 described above. The memory cell 42 is connected to the write word line 43, the read word line 44, the bit line 45, and the GND line 50.

[0063] The MOS transistor 46 includes a first diffusion layer 46a and a second diffusion layer provided in the semiconductor substrate. 46c, and a first gate 46b provided on the semiconductor substrate between the first diffusion layer 46a and the second diffusion layer 46c via an insulating layer. The first diffusion layer 46 a is connected to the GND line 50 via the contact wiring 48. The second diffusion layer 46 c is connected to one end of the lower electrode 1 through the contact wiring 47. The gate 46b is connected to the read word line 44. The lower electrode 1 is connected to one end side of the magnetoresistive effect element 30 (30a) at the other end. The magnetoresistive effect element 30 (30a) is the magnetoresistive effect element (magnetic tunnel junction element) described in the first embodiment or the second embodiment. The magnetoresistive effect element 30 (30a) is connected to the bit line 45 via the upper electrode 31 on the other end side. A write word line 43 is provided on the opposite side to the bit line 45 with respect to the magnetoresistive effect element 30 (30a) via the lower electrode 1 and the interlayer insulating layer 49 so as to be orthogonal to the bit line 45. ing.

 [0064] In the magnetoresistive effect element 30 (30a), the spontaneous magnetization of the free ferromagnetic layer 8 includes the current flowing through the bit line 45 passing over the memory cell 42 and the write word passing under the memory cell 42. It is reversed in the desired orientation by the resultant magnetic field induced by the current flowing in line 43.

 FIG. 19 is a block diagram showing a configuration of the MRAM 60 using the memory cell 42. The MRAM 60 includes a plurality of memory cells 42, a plurality of reference memory cells 42r, a plurality of write word lines 43, a plurality of read word lines 44, a plurality of bit lines 45, an X selector 58, and an X-side current source circuit. 59, an X side current termination circuit 56, a Y selector 51, a Y side current source circuit 52, a read current load circuit 53, a Y side current termination circuit 54, and a sense amplifier 55.

[0066] The memory cells 42 are provided corresponding to the intersections of the plurality of write word lines 43 (the plurality of read word lines 44) and the plurality of bit lines 45, and are arranged in a matrix. The X selector 58 writes a desired selected read word line 44 s during a read operation from a plurality of read word lines 44 and a plurality of write word lines 43 extending in the X-axis direction (word line direction). Sometimes the desired selective write word line 43s is selected. The X-side current source circuit 59 is a constant current source that supplies a constant current during a data write operation to the memory cell 42. The X-side current termination circuit 56 terminates the plurality of write word lines 43. The Y selector 51 selects a desired selected bit line 45s from the plurality of bit lines 45 extending in the Y-axis direction (bit line direction). The Y-side current source circuit 52 is a constant current source that supplies a constant current during a data write operation to the memory cell 42. Read current load circuit 53 This is a constant current source that supplies a predetermined current to the selected memory cell 42 (hereinafter, selected cell 42 s) and the reference memory cell 42 r during the data read operation from the memory cell 42. The Y side current termination circuit 54 terminates the plurality of bit lines 45. The sense amplifier 55 outputs the data of the selected cell 42s based on the difference between the voltage of the reference bit line 45r connected to the memory cell 42r for reference and the voltage of the bit line 45 connected to the selected cell 42s. The

 [0067] Reading data from the memory cell 42 is performed as follows. That is, for the magnetoresistive effect element 30 (30a) of the selected cell 42s corresponding to the intersection of the selected read word line 44s selected by the X selector 58 and the selected bit line 45s selected by the Y selector 51 Thus, a constant current is supplied by the read current load circuit 53. As a result, the selected bit line 45 s has a voltage corresponding to the state of the free ferromagnetic layer 8 of the magnetoresistive element 30 (30a) (the resistance value of the magnetoresistive element 30 (30a)). It becomes. On the other hand, a constant current is similarly supplied to the reference memory cell 42r selected by the bit line 45r and the selected read word line 44s, and the bit line 45r has a predetermined reference voltage. Then, the sense amplifier 55 compares the magnitudes of the two voltages. For example, if the voltage of the selected bit line 45s is greater than the reference voltage, the data of the selected cell 42s is determined to be “1”, and if it is smaller, “0”.

 [0068] Data is written to the memory cell 42 as follows. That is, for the magnetoresistive effect element 30 (30a) of the selected cell 42s corresponding to the intersection of the selected write word line 43s selected by the X selector 58 and the selected bit line 45s selected by the Y selector 51, A magnetic field H in the Y direction and a magnetic field H in the X direction are generated. As a result, a composite magnetic field H is generated.

 Y X

 It is. However, the magnetic field H is applied to the selective write word line 43s by the X-side current source circuit 59.

 Y

 It is generated by flowing a flow. The magnetic field H is applied to the Y-side current source on the selected bit line 45s.

 X

 It is generated when a current having a direction corresponding to the data written by the circuit 52 flows. The magnetoresistive effect element 30 (30a) receives the combined magnetic field H and reverses the direction of spontaneous magnetization so as to correspond to the data to be written.

[0069] By using the magnetoresistive effect element of the first and second embodiments, the quality of the tunnel barrier layer in the magnetic tunnel junction of the magnetoresistive effect element is improved, and the nail coupling magnetic field is made zero. Can improve the characteristics of the magnetic tunnel junction of the magnetoresistive effect element It becomes possible to do. By using this magnetoresistive element for a magnetic random access memory, it becomes possible to improve the manufacturing yield of the magnetic random access memory.

 [0070] According to the present invention, the upper and lower surfaces of the tunnel barrier layer can be made smooth, the quality of the tunnel barrier layer can be improved, and a high MR MRAM can be manufactured. The offset magnetic field can be easily adjusted to zero by setting the nail coupling magnetic field to zero. As a result, it is possible to manufacture an MRAM in which the write current that is strong against the disturbance between the memory cells 42 is kept low.

 In addition to the MRAM, the magnetoresistance effect element of the present invention can also be used in a magnetic head of a magnetic disk device. According to the present invention, the nail coupling magnetic field in the magnetic tunnel junction can be made zero, and the quality of the tunnel barrier layer can be improved.

Claims

The scope of the claims  [1] forming an antiferromagnetic layer on the upper surface side of the substrate;  Forming a first pinned ferromagnetic layer on the antiferromagnetic layer; ^Exposing the first pinned ferromagnetic layer to a gas containing oxygen atoms at a pressure of 5 ^× 10 ^_7 Pa or more and 1 ^× 10 ^_4 Pa or less;  Forming a second pinned ferromagnetic layer on the first pinned ferromagnetic layer;  Forming a tunnel barrier layer on the second pinned ferromagnetic layer;  Forming a free ferromagnetic layer on the tunnel barrier layer;  With  Manufacturing method of magnetoresistive effect element. [2] In the method of manufacturing a magnetoresistive element according to claim 1,!  The film thickness of the second pinned ferromagnetic layer is greater than 0 and less than or equal to lnm  Manufacturing method of magnetoresistive effect element. [3] forming an antiferromagnetic layer on the upper surface side of the substrate;  Forming a first pinned ferromagnetic layer on the antiferromagnetic layer; ^Exposing the first pinned ferromagnetic layer to a gas containing oxygen atoms at a pressure of 5 ^× 10 ^_7 Pa or more and less than 1 ^× 10 ^_4 Pa;  Forming a tunnel barrier layer on the first pinned ferromagnetic layer;  Forming a free ferromagnetic layer on the tunnel barrier layer;  With  Manufacturing method of magnetoresistive effect element. [4] forming an antiferromagnetic layer on the upper surface side of the substrate;  Forming a pinned ferromagnetic layer on the antiferromagnetic layer;  Forming a film including a tunnel barrier layer on the fixed ferromagnetic layer; forming a free ferromagnetic layer on the tunnel barrier layer;  Comprising The film including the tunnel barrier layer has the tunnel barrier layer at the interface with the free ferromagnetic layer based on the average surface roughness of the tunnel barrier layer at the interface with the fixed ferromagnetic layer. The average surface roughness of the layer is formed to be small  Manufacturing method of magnetoresistive effect element. [5] In the method of manufacturing a magnetoresistive element according to claim 4,  The step of forming a film including a tunnel barrier layer includes:  Exposing the pinned ferromagnetic layer to a predetermined atmosphere;  After the exposing step, forming the tunnel barrier layer;  The manufacturing method of the magnetoresistive effect element which comprises this. [6] In the method of manufacturing a magnetoresistive element according to claim 4,  The step of forming a film including a tunnel barrier layer includes:  Exposing the pinned ferromagnetic layer to a predetermined atmosphere;  After the exposing step, forming an additional ferromagnetic layer on the pinned ferromagnetic layer;  Forming the tunnel barrier layer on the additional ferromagnetic layer;  The manufacturing method of the magnetoresistive effect element which comprises this. [7] In the method of manufacturing a magnetoresistive element according to claim 6,  The film thickness of the second pinned ferromagnetic layer is greater than 0 and less than or equal to lnm  Manufacturing method of magnetoresistive effect element. [8] In the method of manufacturing a magnetoresistive effect element according to claims 5 to 7,  Exposing the pinned ferromagnetic layer to a predetermined atmosphere, ^{Exposing the} pinned ferromagnetic layer to a gas containing oxygen atoms at a pressure of 5 ^× 10 ^_7 Pa or more and less than 1 ^× 10 ^_4 Pa  The manufacturing method of the magnetoresistive effect element which comprises this. [9] In the method for manufacturing a magnetoresistive effect element according to any one of claims 1 to 3 and 8,! The step of the first fixed ferromagnetic layer performs exposure to a gas containing the oxygen atom to a magnetoresistive element for exposure to a gas containing 1 X 10 ^_6 Pa or more 1 X 10 ^_5 Pa or less oxygen atoms at a pressure Production method. [10] The method of manufacturing a magnetoresistive element according to any one of claims 1 to 3, 8, and 9. And  The gas containing oxygen atoms is a gas containing at least one of oxygen gas, water, methanol, and ethanol gas.  Manufacturing method of magnetoresistive effect element.  [11] In the method of manufacturing a magnetoresistive effect element according to any one of claims 1 to 10,  The first fixed ferromagnetic layer force comprises a film containing one of CoFe, NiFe, CoFeB, and CoFeCr  Manufacturing method of magnetoresistive effect element. [12] In the method of manufacturing a magnetoresistive effect element according to any one of claims 1 to 11,  The surface roughness of the tunnel barrier layer on the first pinned ferromagnetic layer side is smaller than the surface roughness of the lower layer than the first pinned ferromagnetic layer  Manufacturing method of magnetoresistive effect element. [13] an antiferromagnetic layer formed on the upper surface side of the substrate;  A first pinned ferromagnetic layer formed on the antiferromagnetic layer;  A second pinned ferromagnetic layer formed on the first pinned ferromagnetic layer;  A tunnel barrier layer formed on the second pinned ferromagnetic layer;  A free ferromagnetic layer formed on the tunnel barrier layer;  Comprising  The region of the surface of the first pinned ferromagnetic layer on the second pinned ferromagnetic layer side has a higher oxygen concentration than other regions.  The surface roughness of the first pinned ferromagnetic layer on the tunnel barrier layer side is smaller than the surface roughness of the layer below the first pinned ferromagnetic layer  Magnetoresistive effect element. [14] In the magnetoresistance effect element according to claim 13,  The film thickness of the second pinned ferromagnetic layer is greater than 0 and less than or equal to lnm Magnetoresistive effect element. [15] an antiferromagnetic layer formed on the upper surface side of the substrate;  A first pinned ferromagnetic layer formed on the antiferromagnetic layer;  A tunnel barrier layer formed on the first pinned ferromagnetic layer;  A free ferromagnetic layer formed on the tunnel barrier layer;  Comprising  The surface roughness of the first pinned ferromagnetic layer on the tunnel barrier layer side is smaller than the surface roughness of the layer below the first pinned ferromagnetic layer  Magnetoresistive effect element.  [16] The magnetoresistance effect element according to any one of claims 13 to 15,  The first fixed ferromagnetic layer force comprises a film containing one of CoFe, NiFe, CoFeB, and CoFeCr  Magnetoresistive effect element. [17] a plurality of word lines extending in the first direction;  A plurality of bit lines extending in a second direction substantially perpendicular to the first direction;  The plurality of magnetoresistance effect elements according to any one of claims 13 to 16, provided at each of intersections of the plurality of word lines and the plurality of bit lines.  A magnetic random access memory comprising: